All values in JavaScript, with the exception of null and undefined , contain a set of auxiliary functions and values accessible "through the dot".
Such functions are called "methods", and values - "properties". Let's look at examples.
Example: str.length , str.toUpperCase()
The string has a length property that contains a length:
Strings also have a toUpperCase() method that returns an uppercase string:
If a function is called through a point ( toUpperCase() ), this is called a “method call” if you simply read the value ( length ) - “property retrieval”.
Example: num.toFixed
Numbers have a num.toFixed(n) method. It rounds the number num to n decimal places, if necessary, finishes with zeros to a given length and returns as a string (conveniently for formatted output):
The details of the toFixed work are toFixed in the Numbers chapter
The number method can also be addressed directly:
... But if the number is an integer, then there will be a problem:
The error will occur because JavaScript expects a decimal after a point.
This is a feature of JavaScript syntax. This is how it will work:
Pay attention, for the method call after its name there are brackets: hello.toUpperCase() . Without brackets the method will not be called.
Let's see, for example, the result of a call to toUpperCase without brackets:
This code displays the value of the toUpperCase property, which is a function embedded in the language. Typically, the browser displays it something like this: "function toUpperCase() { [native code] }" .
To get the result, this function must be called, and just for this in JavaScript brackets are required:
We will meet with lines and numbers in later chapters and learn more about the means to work with them.
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Scripting client side JavaScript, jqvery, BackBone
Terms: Scripting client side JavaScript, jqvery, BackBone